Patent Number: 6,308,531

Title: Hybrid cycle for the production of liquefied natural gas

Abstract: Refrigeration process for gas liquefaction which utilizes one or more vaporizing refrigerant cycles to provide refrigeration below about -40.degree. C. and a gas expander cycle to provide refrigeration below about -100.degree. C. Each of these two types of refrigerant systems is utilized in an optimum temperature range which maximizes the efficiency of the particular system. A significant fraction of the total refrigeration power required to liquefy the feed gas (typically more than 5% and often more than 10% of the total) can be consumed by the vaporizing refrigerant cycles. The invention can be implemented in the design of a new liquefaction plant or can be utilized as a retrofit or expansion of an existing plant by adding gas expander refrigeration circuit to the existing plant refrigeration system.

Inventors: Roberts; Mark Julian (Kempton, PA), Agrawal; Rakesh (Emmaus, PA)

Assignee: Air Products and Chemicals, Inc.

International Classification: F25J 1/00 (20060101); F25J 1/02 (20060101); F25J 001/00 ()

Expiration Date: 10/30/2018